The recording industry's case against file-swappers is that it deprives them of revenue that they would otherwise have received for the music that gets shipped around. (Well, actually, they talk about the money that would have gone to the artists, but most of them wind up seeing bupkes).

The RIAA just settled their lawsuit against a 12-year-old girl from a New York City housing project who'd downloaded new music, for $2000. I'm sure that's comparable to the revenue they actually lost on her purchases. Why ever would they have sued otherwise?